From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3AEC7C77B73 for ; Wed, 19 Apr 2023 14:23:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233355AbjDSOXP (ORCPT ); Wed, 19 Apr 2023 10:23:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50972 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233100AbjDSOXA (ORCPT ); Wed, 19 Apr 2023 10:23:00 -0400 Received: from mail-pf1-x42f.google.com (mail-pf1-x42f.google.com [IPv6:2607:f8b0:4864:20::42f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6D8FB7DAD for ; Wed, 19 Apr 2023 07:22:51 -0700 (PDT) Received: by mail-pf1-x42f.google.com with SMTP id d2e1a72fcca58-63b62d2f729so2471173b3a.1 for ; Wed, 19 Apr 2023 07:22:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=dabbelt-com.20221208.gappssmtp.com; s=20221208; t=1681914171; x=1684506171; h=content-transfer-encoding:mime-version:message-id:to:from:cc :in-reply-to:subject:date:from:to:cc:subject:date:message-id :reply-to; bh=PqMbvZWHdx/umNn2GDsuDcOtpXqKSdzh2puSjeFvGNg=; b=BQQfPjXj9RjzqoAPS+lEslGY5dDcNNPEbJrUbMfagQ00SpueZWLcpYAadUOn4K2r/7 h4HdkG7hv1lk/JwJJQYCK1kCSiFRuTmkN44fcy7kPteadqn38MkQ3ndJHP2Mc9t7NrZL nmp1DYP7b7nPYrKCi/AHIrNyGwWhrPzKd1bjeAAqOo6tX3/AL+K+6SRGBPhAsfYsDgSs dPS/aO0HTzlFjGLxzQlmfHBIIf93KsDsbdHG4ySz5E0QxtwHAyLnkpkj20M9cIgvdPfV aEw0KFtyNn5lgDQSa9YMyBJglZh/UHtAgTzAA5ieEsZiecFBH/5j299y8tclByk2q0hU dWkg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1681914171; x=1684506171; h=content-transfer-encoding:mime-version:message-id:to:from:cc :in-reply-to:subject:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=PqMbvZWHdx/umNn2GDsuDcOtpXqKSdzh2puSjeFvGNg=; b=Pr402ejarJSDnbf30QSp+mBSzPkiNNxbP8pclqd3NuDd2cHVzO/Gclzyy6vY7ncH/O YBDHTEf7JL+Anz5qWirjmWEv/D/F667uwbL9tx+S3ed3ciWgJ/JY5C8jTs5a0cJoyaz4 iZZb8iU37v42qegHKQO05JEux8kbtidCA7CwrGoS7yDTQcxR54mDJimYgC65pNSFsKZd MkTPeIJBpTVtV1Q47M7FNpRRi5BfqF8fCfVLG3BHzZnqjzV0P4V7jeYcqbFSRq+J6vCp 8UPyoQg0Ry4WA9AI9shBFSg2165hcpRFE9rGXsJfZoiUgJPUxrAYvTclBN2uX79NMW9s jUPg== X-Gm-Message-State: AAQBX9evPTQ45Ov7p1c/OT/HoEHlxPpcTmHl6qbN4rWScYWO+x1mFzCQ btsgNCxSdAiHhVjDCRjVF7ElGg== X-Google-Smtp-Source: AKy350bZHj+5SLgwTf96Z4FllovZ8h4/H1ZYpgVXzzdS4Hiiw7gNLDstVjX8e8aaqlbpRvsz3GY15A== X-Received: by 2002:a05:6a00:2355:b0:63b:8778:99f7 with SMTP id j21-20020a056a00235500b0063b877899f7mr4656389pfj.9.1681914170729; Wed, 19 Apr 2023 07:22:50 -0700 (PDT) Received: from localhost ([135.180.227.0]) by smtp.gmail.com with ESMTPSA id j7-20020aa78dc7000000b0063b806b111csm7467077pfr.169.2023.04.19.07.22.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 19 Apr 2023 07:22:50 -0700 (PDT) Date: Wed, 19 Apr 2023 07:22:50 -0700 (PDT) X-Google-Original-Date: Wed, 19 Apr 2023 07:22:40 PDT (-0700) Subject: Re: [PATCH 08/21] riscv: dma-mapping: only invalidate after DMA, not flush In-Reply-To: <20230327121317.4081816-9-arnd@kernel.org> CC: linux-kernel@vger.kernel.org, Arnd Bergmann , vgupta@kernel.org, linux@armlinux.org.uk, neil.armstrong@linaro.org, linus.walleij@linaro.org, Catalin Marinas , Will Deacon , guoren@kernel.org, bcain@quicinc.com, geert@linux-m68k.org, monstr@monstr.eu, tsbogend@alpha.franken.de, dinguyen@kernel.org, shorne@gmail.com, deller@gmx.de, mpe@ellerman.id.au, christophe.leroy@csgroup.eu, Paul Walmsley , dalias@libc.org, glaubitz@physik.fu-berlin.de, davem@davemloft.net, jcmvbkbc@gmail.com, Christoph Hellwig , robin.murphy@arm.com, prabhakar.mahadev-lad.rj@bp.renesas.com, Conor Dooley , linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-oxnas@groups.io, linux-csky@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-openrisc@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-xtensa@linux-xtensa.org From: Palmer Dabbelt To: arnd@kernel.org Message-ID: Mime-Version: 1.0 (MHng) Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org On Mon, 27 Mar 2023 05:13:04 PDT (-0700), arnd@kernel.org wrote: > From: Arnd Bergmann > > No other architecture intentionally writes back dirty cache lines into > a buffer that a device has just finished writing into. If the cache is > clean, this has no effect at all, but if a cacheline in the buffer has > actually been written by the CPU, there is a drive bug that is likely > made worse by overwriting that buffer. > > Signed-off-by: Arnd Bergmann > --- > arch/riscv/mm/dma-noncoherent.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/riscv/mm/dma-noncoherent.c b/arch/riscv/mm/dma-noncoherent.c > index d919efab6eba..640f4c496d26 100644 > --- a/arch/riscv/mm/dma-noncoherent.c > +++ b/arch/riscv/mm/dma-noncoherent.c > @@ -42,7 +42,7 @@ void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size, > break; > case DMA_FROM_DEVICE: > case DMA_BIDIRECTIONAL: > - ALT_CMO_OP(flush, vaddr, size, riscv_cbom_block_size); > + ALT_CMO_OP(inval, vaddr, size, riscv_cbom_block_size); > break; > default: > break; Acked-by: Palmer Dabbelt